Search Results (216)

Plastic manufacturing involves using compounds that could be considered endocrine disruptors. Consequently, concern about the effect of these particles on the hormonal regulation of various systems, including the hypothalamic–pituitary–thyroid axis, has been increasing. By applying the Amphibian Metamorphosis Assay (AMA), the effects of irregular polystyrene microplastics (PS) MPs on the thyroid gland of Xenopus laevis were investigated. The histological effects on other organs of tadpoles were also studied. Tadpoles were exposed to 500 and 50 µg of virgin PS MP particles, (200 µm range)/L, administered by diet for 21 days. PS dietary exposure revealed statistically significant effects for the snout to vent length and the whole body length apical endpoints on day 21. The histological survey of both treatment groups revealed no noteworthy effects on the thyroid gland, digestive tract, or kidneys, but slight modifications to the liver. Mild ultrastructural modifications were detected in tadpoles’ enterocytes and hepatocytes in both treatment groups, but were likely to be reversible. Overall, our results contrast with previous research results in which effects were observed, but using different types, concentrations, and numbers of MPs. All this suggests the need for standardized methods for the environmental risk assessment of MPs/NPs (nanoplastics). Concern about the risk of NPs seems to be greater, and more studies with NP particles should be conducted. Full article

Integrating recyclates into food packaging is key towards circularity while meeting functionality and safety requirements; however, associated environmental impacts remain underexplored. This gap was addressed through a cradle-to-gate life cycle assessment, using the Environmental Footprint method, along with substitution and cut-off approaches for handling the multifunctionality of recycling. Recyclates were derived from polyethylene (PE)-rich household food packaging waste, purified via delamination-deinking. Firstly, results show that shifting from virgin multi-material to mono-material multilayer structures with or without recyclates, while maintaining functionality, offers environmental benefits. Secondly, recyclates should sufficiently substitute virgin materials in quantity and quality, decreasing the need for primary plastics and avoiding recyclate incorporation without functionality. Otherwise, thicker laminates are obtained, increasing processability challenges and environmental impacts, e.g., 12% for particulate matter, and 14% for mineral-metal resource use when the recycle content rises from 34 to 50%. Thirdly, a fully closed loop for flexible food packaging is not yet feasible. Key improvements lie in reducing residues generated during recycling, especially in delamination-deinking, lowering energy use in recompounding, and using more efficient transport modes for waste collection. Further research is essential to optimise the innovative technologies studied for flexible food packaging and refine them for broader applications. Full article

In order to recycle plastic waste back to food contact materials (FCMs), it is necessary to identify hazardous substances in plastic packaging that pose a toxicological risk. Printing inks on plastics are not yet designed to withstand the high heat stress of mechanical recycling processes and therefore require hazard identification. In this study, virgin polypropylene (PP) foils were printed with different types of inks (UV-cured, water-based) and colour shades. Thermal analysis of printed foils and pigments was performed using differential scanning calorimetry (DSC). Samples were then thermally treated below and above measured thermal events at 120 °C, 160 °C, 200 °C or 240 °C for 30 min. Subsequently, migration tests and miniaturised Ames tests were performed. Four out of thirteen printed foils and all three pigments showed positive results for mutagenicity in miniaturised Ames tests after thermal treatment at 240 °C. Additionally, pre-incubation Plate Ames tests (according to OECD 471) were performed on three pigments and one printed foil, yielding two positive results after thermal treatment at 240 °C. These results indicate that certain ink components form hazardous decomposition products when heated up to a temperature of 240 °C. However, further research is needed to gain a better understanding of the chemical processes that occur during high thermal treatment. Full article

International waste policy promotes the reduction and re-use of waste materials, and in some cases, specifically calls for the use of recycled materials in pavements. In countries like Australia, most of the aircraft pavement network is constructed of flexible pavements. Consequently, understanding the opportunities for recycled materials in flexible aircraft pavements is paramount to increasing the technology uptake. This paper reviews opportunities for the incorporation of recycled materials in flexible airport pavement construction, specifically, their application to particle substitution in unbound and asphaltic layers, use in stabilization treatments, and use as a bitumen modifier. Additionally, environmental product declarations are reviewed to provide a range of typical environmental costs for each recycled material when considering material processing for incorporation into flexible pavements. These materials are compared to virgin material environmental costs to determine which recycled materials provide the highest environmental benefit potential. It was concluded that particle replacement in unbound layers with waste materials had a similar environmental cost to using virgin materials. However, the requirement to dispose of waste material to the landfill can be significantly reduced. For asphaltic layers, recycled asphalt pavement as an asphalt mixture replacement, fly ash as a hydrated lime replacement, and waste plastic and crumbed rubber as a virgin polymer replacement all are effective in reducing the environmental cost. To further increase the technology uptake, a risk-based approach for the implementation of waste materials in airport flexible pavements is recommended, which considers performance testing, the depth of the pavement layer, and the pavement functional area. Full article

This study presents the development of a sustainable composite material by incorporating by-products from the cork industry into acrylonitrile butadiene styrene (ABS), with the aim of reducing the environmental impact of plastic composites while maintaining their performance. ABS, a petroleum-based polymer, was used as the matrix, and maleic anhydride (MAH) with dicumyl peroxide (DCP) served as a compatibilizing system to improve interfacial adhesion with cork microparticles. Composites were prepared with 10% w/w cork in various particle sizes and characterized via FTIR, X-ray computed tomography, SEM, mechanical testing, and thermal analysis. The best performing formulation (CPC-125) showed a reduction of only ~16% in tensile modulus and ~7% in tensile strength compared with ABS-g-MAH, with a more pronounced decrease in strain at break (3.23% vs. 17.47%) due to the cork’s inherent rigidity. Thermogravimetric and calorimetric analysis confirmed that thermal stability and processing temperatures remained largely unaffected. These results demonstrate the feasibility of incorporating cork microparticles as a bio-based reinforcing filler in ABS composites, offering a promising strategy to reduce the use of virgin plastics in applications compatible with conventional injection molding. Full article

Neurodegenerative disorders, mental conditions, and cognitive decline represent significant challenges worldwide, with growing pieces of evidence implicating alterations in neurotrophin signaling as central to these diseases. Neurotrophins—such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF)—are indispensable for neuronal survival, differentiation, and synaptic plasticity, and their dysregulation is closely associated with various neuropathological situations. Similarly, dietary plant polyphenols, abundant in vegetables, fruits, wine, tea, and extra virgin olive oil, show powerful anti-inflammatory, antioxidant, and anti-apoptotic activities. This narrative review critically addresses the evolving body of evidence that links plant polyphenols and brain neurotrophins, emphasizing several molecular mechanisms by which polyphenols regulate and modulate neurotrophin signaling. Crucial pathways include mitigation of neuroinflammatory responses, activation of intracellular cascades such as the cAMP response element-binding protein (CREB), epigenetic modulation, and the diminution of oxidative stress. Together, these effects contribute to potentiated enhanced synaptic function, neuronal integrity, and better learning and memory processes. Moreover, this narrative review examines how polyphenol-induced upregulation of neurotrophins may alleviate conditions associated not only with neurodegeneration but also with addiction and mood disorders, suggesting extensive therapeutic approaches. Findings from clinical investigations and animal models are presented to sustain the neuroprotective role of polyphenol-rich diets. Lastly, future research directions are recommended, focusing on polyphenol bioavailability optimization, considering combinatory dietary stratagems, and proposing personalized nutritional interventions. This wide-ranging perspective highlights plant polyphenols as encouraging modulators of neurotrophin pathways and supports their inclusion in approaches aimed at promoting brain health and counteracting neurodegenerative decline. Full article

The escalating production of virgin plastics has resulted in an unprecedented generation of microplastics (MPs), posing significant environmental and health risks. Biodegradable plastics have emerged as an alternative, but their degradation also releases microplastic-sized particles, referred to as biodegradable microplastics (BMPs). This review evaluates the current understanding of BMPs, focusing on their environmental fate, degradation kinetics, and comparative persistence relative to conventional MPs. The degradation process of biodegradable plastics involves sequential abiotic and biotic mechanisms, with factors such as polymer chemistry, geometry, and environmental conditions influencing BMPs’ formation and mineralization. Studies highlight the temporal advantage of BMPs, which exhibit significantly shorter lifetimes than traditional MPs; however, their environmental impact remains context-dependent, particularly in soil and aquatic systems. Despite promising results under controlled conditions, challenges in standardizing biodegradation assessments and discrepancies between laboratory and real-world scenarios complicate evaluations of the temporal fate and the effects of BMPs. This work underscores the need for long-term studies and improved modeling approaches to accurately predict BMP behavior and mitigate their ecological impact. Poly(hydroxyalkanoates) are a class of fully biodegradable polymers that do not leave behind persistent microplastics. Biodegradable plastics should be prioritized over non-degradable, traditional polymers, as they can replace them in a large fraction of applications, yet with a significantly reduced footprint and without leaving behind persistent micro- and nanoplastics. They can also be recycled. Full article

Waste fires are significant sources of atmospheric pollutants that contribute to environmental degradation and public health risks. They also lead to considerable losses in recyclable materials and energy. In Poland, waste fire incidents have increased in recent years, peaking in 2018–2019. This study quantifies the volume and mass of waste burned and assesses the associated losses in material and energy potential. A detailed incident inventory was compiled, including waste types and burned volumes, which were converted to mass values. This study estimates the potential fate of this waste under proper waste management scenarios. Recyclable materials, such as plastics, metals, paper, textiles, and rubber, are permanently removed from circulation, increasing the reliance on virgin resources. Energy losses were calculated using the lower heating values of each waste type, assuming a full energy recovery potential. In 2018, large and very large fires resulted in an estimated 170,000–1,016,640 m³ of burned waste, with corresponding energy losses of 495–2970 TJ. In 2019, estimates ranged from 68,000–410,000 m³ and 139–831 TJ. Plastics, refuse-derived fuel (RDF), and tires accounted for the majority of these losses. These findings highlight the relevance of waste fires in undermining recycling or energy recovery efforts and slowing progress toward a circular economy. Full article

The growing volume of plastic waste from end-of-life vehicles presents environmental concerns, driving efforts to integrate recycled plastics. This study investigates the possibility of using recycled plastic from automotive parts (painted and unpainted bumpers, fuel tanks) as a 10% filler in the core layer of three-layer particleboards (P) and evaluates its impact on physical properties (water absorption—WA and thickness swelling—TS), mechanical properties (internal bonding strength—IB, modulus of rupture—MOR, modulus of elasticity—MOE and screw driving torque—SDT) and volatile organic compounds—VOC emissions. The boards were produced using conventional hot-pressing technology and analyzed according to applicable standards. Based on the results, the density of the reference (P) was 0.72 g·cm⁻³, while wood–plastic composites ranged from 0.70 g·cm⁻³ to 0.72 g·cm⁻³. After 24 h, WA reached 40% for reference (P) and from 36.9% (for (P) containing unpainted bumpers) to 41.9% (for (P) containing fuel tanks). TS reached 18% for (P) and from 16.8% (for (P) containing unpainted bumpers and fuel tanks) to 18.1% (for (P) containing painted bumpers). Plastic is a hydrophobic material and it is assumed that by increasing the proportion of plastic filler in the particleboards, the WA and TS of prepared boards will decrease. From the point of view of mechanical properties, values for (P) containing plastic filler were slightly lower compared to reference (P). The lowest value of IB (0.39 MPa) were reached for (P) containing painted bumpers. Plastic surface treatment could interfere with adhesion between the plastic and adhesive, weakening the bond in the core layer. For this reason, is preferable to use unpainted fillers, which provide better adhesive properties and higher structural integrity. VOC emissions from wood components consisted primarily of monoterpenes such as α-pinene, 3-carene and limonene. Adding 10% plastic to the particleboard did not increase overall VOC emissions. On the other hand, combining wood and plastic particles resulted in a reduction in overall VOC emissions. The findings confirm that recycled automotive plastics can be effectively incorporated into particleboards, maintaining standard performance while reducing reliance on virgin wood materials, making them a viable and sustainable alternative for furniture and interior applications. Full article

In this study, a microwave-assisted sulfuric acid recovery method is proposed for the efficient recovery of high-value carbon fibers at 100–140 °C. The recycled carbon fibers (RCF) were characterized, and recycled carbon fiber-reinforced plastics (RCFRP) were fabricated using their fibers. The recycling process preserved the surface morphology of the carbon fibers, with the RCF maintaining the axial groove structure on the surface of the virgin carbon fiber (VCF). X-ray diffraction (XRD) and Raman spectroscopy analyses confirmed that the degree of graphitization and crystalline structure of the RCF remained largely unchanged compared to the original carbon fibers. Surface oxidation occurred during the recycling process, leading to an increase in O–C=O content on the surface of the RCF compared to that of the VCF, which facilitated interfacial chemical bonding with the resin and enhanced the wettability. Compared to virgin carbon fiber-reinforced plastics (VCFRP), RCFRP retained up to 95.25% of the tensile strength, 97.47% of the shear strength, and 96.76% of the bending stress, demonstrating excellent mechanical properties. This study provides a simple and effective approach for the low-temperature and high-efficiency recycling of carbon fiber composites. Full article

As the severe environmental impacts of plastic pollution demand determined action, the European Union (EU) has included recycling at the core of its policies. Consequently, evolving jurisdiction now aims to achieve a recycling rate of 65% for non-PET plastic bottles by 2040. However, the widespread use of post-consumer high-density polyethylene (rPE-HD) recyclates in household chemical containers is still limited by PP contamination, poor mechanical properties, and low environmental stress cracking resistance (ESCR). Although previous studies have explored the improvement of regranulate properties through additives, few have examined whether reducing the variety of extrusion blow-moulded PE-HD packaging could offer similar benefits. Therefore, two sorted fractions of rPE-HD hollow bodies were processed into regranulates under industrial conditions, including hot washing, extrusion, and deodorisation. Subsequently, both materials underwent comprehensive characterisation regarding their composition and performance. The opaque material, which was sourced from milk bottles in the UK, exhibited greater homogeneity with minor impurities, leading to improved ductility and melt strain hardening at moderate strain rates compared to the mixed material stream, which contained approximately 2.5% PP contamination. However, both rPE-HD recyclates exhibited similar short-term creep behaviour, relatively low strain hardening moduli, and were almost devoid of inorganic particles. Considering the sum of the investigated properties, melt blending with suitable virgin material is likely one of the most effective options to maximise regranulate utilisation in hollow bodies, followed by recycling-oriented packaging design (e.g., for efficient sorting), and the employment of advanced sorting technology. Full article

This study underscores the importance of sustainable practices by exploring the utilization of recycled plastic within the global construction industry. Plastic recycling has emerged as a crucial strategy that aligns with environmental, social, and economic sustainability indicators. Currently, substantial volumes of plastic waste are either deposited in landfills or incinerated, neglecting the potential to harness its embodied energy and the energy consumed for producing virgin materials. A key advantage of plastic lies in its promising mechanical properties. Concrete mix design is fundamental to a wide range of construction applications, including brick walls, reinforced concrete slabs, and concrete pavements. Despite the adoption of recycled plastic in construction materials in various countries, its widespread implementation remains limited. This is primarily due to the scarcity of experimental research in this area and the absence of a robust waste management system. This research specifically investigates the reuse of two common types of plastic waste: polyethylene terephthalate (PET) and high-density polyethylene (HDPE) to mitigate plastic waste accumulation in landfills and enhance the performance of construction materials. The study investigates the use of recycled HDPE and PET as a replacement for coarse aggregates in concrete pavement mixtures. While recycled PET is more prevalent in concrete applications, recycled HDPE has demonstrated exceptional efficiency and durability. The recycling method used in this research is the mechanical recycling method due to its superior effectiveness in comparison with other methodologies. This research assesses the performance of recycled PET and HDPE in concrete pavement, aiming to diminish non-renewable energy consumption by 15–20%, curtail the carbon footprint by 15–30%, and decrease plastic waste in landfills by 20–30% compared to conventional concrete. Full article

Assessing the detailed characteristics of recycled plastics is essential for evaluating their quality and suitability for high-value applications compared to virgin polymers. This review provides a comprehensive overview of advanced analytical techniques used for characterizing the chemical, structural, morphological, and physical properties of recycled polymeric materials. The techniques examined include Fourier Transform Infrared Spectroscopy (FTIR), Micro-Raman spectroscopy, X-ray Fluorescence (XRF), Inductively Coupled Plasma (ICP) techniques, X-ray Powder Diffraction (XRPD), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM). These methods are critically assessed for their effectiveness in detecting polymer degradation, surface and structural alterations, and the presence of contaminants—factors frequently introduced during mechanical recycling processes. For each technique, this review outlines the working principles, sample preparation protocols, and illustrative case studies while discussing their advantages, limitations, and operational challenges. By synthesizing current knowledge and methodological advancements, this review aims to support the development of robust and standardized quality assessment protocols. Enhancing the reliability and precision of recycled plastic characterization will improve their acceptance as high-quality secondary raw materials, thereby facilitating their upcycling and contributing to the broader goals of the circular economy. Full article

The extensive use of polyolefins, such as polyethylene (PE) and polypropylene (PP), has led to a substantial accumulation of plastic waste, raising growing concerns about environmental impact and sustainability. In this study, the dielectric, thermal, and chemical properties of recycled materials were investigated, and blending with virgin polyethylene was examined as a sustainable strategy to enhance their electrical performance and promote material reuse. Dielectric analysis demonstrated that blending recycled materials with virgin polyethylene effectively reduced dielectric losses. With the addition of only 15% virgin HDPE, the dielectric loss was significantly lowered by 40% for recycled HDPE (rHDPE) and 30% for the recycled PE-PP blend (r(PE-PP))—compared to their unblended forms. Although the original recycled materials exhibited much higher dielectric losses than virgin HDPE—24 and 28 times greater for rHDPE and r(PE-PP), respectively, at 60 Hz—the blending approach clearly improved their electrical behavior. Overall, the results highlight blending as a practical and sustainable strategy to improve the dielectric performance of recycled polyolefins, enabling their reuse in applications such as electrical cable insulation while contributing to plastic waste reduction. Full article

Polypropylene (PP), a widely used recyclable plastic in packaging and engineering applications, is prone to thermo-oxidative degradation during reprocessing and molding at high temperatures. Antioxidants (AOs) are essential for stabilizing PP in both its virgin and recycled states. The quantity of AO added is critical: insufficient amounts can lead to poor stabilization, while excessive amounts can cause safety concerns due to build-up. This study presents a modified approach to measure the Oxidation Induction Temperature (OIT) using Differential Scanning Calorimetry (DSC), particularly for recycled PP from waste that contains unpredictable contaminations. This modified approach ensures the safety of the calorimetry cell by limiting the oxidation reaction and preventing the release of volatile compounds during measurements. By performing DSC measurements in inert environments, we obtain the OIT, which can be correlated to residual intact AO levels. This approach to monitoring AO levels is demonstrated in both open- and closed-loop recycling of rigid PP. Although the presence of contamination is known to catalyze thermo-oxidative degradation in PP, our results indicate that recycled PP from open-loop collection still contains sufficient residual AO that allows it to withstand limited thermal reprocessing. However, this tendency of AO retention leads to significant build-up during closed-loop recycling when AOs are added to each cycle, where the PP grade remains fairly homogeneous and the dispersity (Đ) does not significantly increase over multiple recycling loops. Full article